(1) Field of Embodiments
The present invention refers to a self-locking connecting device according to the preamble of independent claim 1.
The privileged fields of application of this kind of device are jewelry and clockmaking.
(2) Description of Related Art
The basic problem that is encountered is the perfect safety of the connection and the reliability of the latter, combined, first of all, with a simple, quick, and comfortable operation of the device, furthermore with a rational and subtle construction of the latter that allows a manufacture at minimum cost and a genuine polyvalence both in its applications and in its usage, and ultimately, more particularly if it is intended for use in jewelry or clockmaking, with a sober, discrete, and attractive esthetic, which implies a harmonic shape and overall dimensions that are reduced to the minimum.
The types of connecting devices known in the art are quite numerous. However, they are still affected by more or less marked drawbacks with regard to all or part of this problem.
Among the best known connecting devices, commonly called clasps, the spring ring clasp may be cited, which is formed of a hollow ring that is cut on a segment and of a pin that can be operated to open or close that segment and has the same curvature as the latter, which pin is under the action of a spring accommodated in the ring. The latter is attached to one end of a necklace. The loop of a chain link or of another ring connected to the second end of the necklace can be inserted therein through the open segment while the pin that closes the ring is moved against the action of the spring. The pin is then released, thereby reclosing the ring. This system is thought to be inelegant as it is ill adapted to the shape of the necklace, bulky, and heavy. Moreover, it often requires an additional safety.
Moreover, when the clasp is fastened to a short necklace, it is located behind the neck of the person wearing it. In order to manipulate the clasp of the necklace, the person has to operate blindly and his or her arms are in a tiring position. If the person fails to insert the two elements of the clasp into each other right away, successive trials and fumbling will be the result. This uncomfortable manipulation may lead to an incomplete lock, and the clasp may sometimes be undone by accident.
FR-A-2 694 485 discloses a locking device comprising a body with two pivoting elements and a male end portion whose shape corresponds to that of a recess in a housing of the body. When the male end portion is introduced into the recess of the body, a key can be pivoted and placed in a receptacle of the end portion. A cover ensures the closure by preventing an involuntary retraction of the key.
FR-A-2 531 322 describes a clasp for a necklace chain that comprises two pieces sliding one in the other, namely an outer sleeve provided with a slot for introducing an end link of the chain and an inner slide element provided in its upper part with a notch for receiving the link. This clasp further comprises a locking tooth that is connected to the slide element and is engaged in an aperture of the slide element in the locking position.
However, these clasps do not offer an acceptable solution to the aforementioned drawbacks.
FR-A-2 611 452 discloses a clasp composed of a male part and a female part which cooperate with each other by the implementation of a snap function. This clasp provides an improvement in that it seems to offer a satisfactory closure safety and to allow quite an easy operation by feel. In contrast, the opening operation is very uncomfortable, the production, i.e. the manufacture of the clasp is delicate and costly, and its esthetic is all but fortunate.